The Aintree intubation catheter is a blunt-tipped, 19 Fr, radio-opaque catheter with an internal diameter of 4.7 mm. It has centimeter markings from 5 to 35 cm on the outside to help with placement.
The catheter is supplied with two Rapi-Fit® connectors, one with a standard 15 mm tube connector and the other one with a Luer-lock connector. The kit also includes a soft-seal swivel adaptor to allow ongoing ventilation whilst placing the catheter.
The two Rapi-Fit® connectors supplied with the Aintree intubation catheter kit
The standard 15 mm Rapi-Fit® connector attached to the Aintree catheter
The catheter is just short enough to fit completely over an standard adult flexible fiberoptic bronchoscope, leaving enough space at the end of the scope for flexing the bending section to navigate.
The manufacturer's recommendations state that an endotracheal tube need to be of an internal diameter of 7.0 mm or greater to accommodate the Aintree intubation catheter. In practice, a 6.5 mm ET tube is the smallest suitable size, but with a somewhat tight fit (a 6 mm ET tube is definitely too small).
A size 6.0 ET tube does not fit over an Aintree intubation catheter (left picture); the smallest ET tube which accommodates the device is a 6.5 ET tube (right picture)
It is probably best to use a 6.5 or 7 mm ET tube with the Aintree catheter and avoid larger ET tube sizes as a large 'step-up' between the Aintree catheter and the ET tube can lead to the tube getting caught at the vocal chords, making the passing of the ET tube difficult with the risk of trauma (see picture below). If a large ET tube, i.e. size 8.0 or greater, is required, it might be advisable to use a Parker Flex-Tip tube®.
Approximately 2 cm from the distal opening the Aintree intubation catheter has a small side hole on each side to prevent 'whipping' of the catheter inside the patient's airway if jet ventilation is used.
The Aintree intubation catheter is primarily used for intubating through a laryngeal mask with fiberoptic guidance.
Another indication for its use is the exchange of an endotracheal tube, although other devices are preferable, such as the Cook airway exchange catheter or the gum-elastic bougie.